There are at least two general types of conveyors; static i.e. rollers rotate to drive the goods along but do not themselves move; dynamic i.e. a belt moves carrying the goods with it. Rollers may also be used in dynamic systems to drive and/or support the belt but are not the conveying mechanism in this type of conveyor. There are a number of problematic areas with these conveyors. One such area relates to the use of various drive mechanisms and support structures which are accessible to the conveyed goods and which establish voids, corners and other places where the goods or particles of goods can become lodged. This is especially problematic when the goods are small and can become damaged themselves or can become enmeshed, alone or in an accumulation, with the drive apparatus and cause it to bind or be damaged. This problem is magnified in the food processing industry where the goods can decay and form harmful substances. In such applications elaborate, frequent washings and immersions of the entire conveyor system are often necessary to ensure sanitary conditions.
Generally there is provided specific guiding and support means for belted conveyors and the various support structures and drive apparatus are disposed wholly, or extend at least partially externally to the sides of the conveyor. This increases the space required for such conveyors and the hazards associated with working near them.
Rollers used in conveyor systems either as the primary conveying mechanism or the drive and/or support means for belting are generally of the type in which one end shaft is retractable to permit installation of a roller having a length approaching as nearly as possible the distance between the side supports for the rollers and to minimize the enlargment of the shaft hole required to enable installation. Such rollers with retractable mechanisms are expensive but are typically preferred to the alternative approach which requires a much enlarged shaft hole and a roller whose length is significantly less than the distance between the side support members.
Tension adjusting means such as used with belted conveyor systems require substantial support and guide structures to vary and to maintain tension settings on heavily loaded conveyors.